Rotor for multistage turbines and compressors



Dec. 27, 1949 K. BAUMANN ROTOR FOR MULTISTAGE TURBINES AND COMPHESSCRSFiled Nov. 19, 1946 INVENTOR WI ATTORNEYS Patented Dec. 27, 1949 PATENTorelce uutrrsraor TURBINES si ner to Met e!) q atbriie l i litamvickersE ec r cal C di Leii n land, a com any o Application November 19, 1246,Serial No. 710,762

' In Great Britain November 1945 Clam 1 This in en ion l e to a ro or fr multista e turbines an r sso s, e dn ertleuler to bladed rotorstherefor.

In the design of rotors having several rows of blades for use i h e-speed-mul i=stese-turbines or compressors, ther are, as he number anddiameter of the bladi sta es inc ea serio s limitations to the useofrotor constructions: of the drum type and also of the type inv vingseparate discs mounted u on a shaf th se lime itations being accentuatedin circumstances W ere m nimisa ion .ef eve a Wei t-is su eially mpotant a fo exam e, is the ease wit t rotors of turbines o com ress rs intnd d for use on a rc af mor particu ar in the f a rot r o th rum t e, hho p s r s is ab to bec me i ssiv w h eased i mr eter or i -dine pee Whin t eaeee e rotor of the multi-disc type, the diameter of the shaitmust be increased correspondingly with increase n he numb r d ll en h os ages in o e he? the r ti al s eed ha b meieie ed Wit a onab lim nd tsu h iher e ha ame r h 1 S e a t b liable to become excessive and tocause shrinkage fit between the discs and shaft a con e uenc u t s hiieeee 9f t biae In e er to e o e imita i s ei to, resource has beenmade to theuse of a r constr ti n in lv g a l r it o dispslt. abuttingtogether at projections termed solid with the discs at-a diameterconsiderably greater than that of the usual bores. With such c 11,-.struction a rigid structure having relatively h gh e r ii el speed ister in which the d ee'ere held together at spigoted locations of contactby m ans of a ol passin thr eh el t vely small holes in the hubs, oralternatively by welded unions between the projections on thefdiscsi;this latter method is, however, unsatisfactory inasg much as, with thewelding applied t [at of the disc proper, local stresses are uire ueedinto disc, and si j e ghl stre se membe s ch leea gm] projection, 'or'several circularly-distributed projections, facing and in axialalignment .5 5

a similar projection or projections on the adja: cent disc, and theprojection or projections on one disc being secured by pinning orriveting or bolting to an annular member which is rigidly attached, bywelding, to an annular member'selcured by pinning or riveting or boltingt9 thepro; jection or projections on the adjacent disc,

Inasmuch as such welding as is utilised in effooting attachment betweenthe discs is notaps plied directly to a disc proper, but on the.contrary to a member which is secured to the disc by being pinned,riveted or bolted to the disc projeo; ti'ont's), the possibility ofintroduction of local stresses into the disc proper is minimised.

"Adva'ntageously provision should be madeyfor clearance between theprojection, or projections, on a disc and the annular member which isse;curedthereto by pinning or riveting or bolting, so that duringapplication of Welding to said annular member (for attaching it to theannular member which is secured by pinning or riveting or bolting to theprojection or projections of the adjacent disc) said annular member. canexpand freely and with but minimum application of stress to the disc dueto engagement .of said an: nular member with said projection .or prolenstions ofthe disc.

In carrying out the invention it isspreferable for the annular membersecured to the projection or projections on one disc to be spigotedwithrespect to the annular member secured to the projection orprojections on the adjacent disc; advantageously the'annular member forone disc may be machined on a radial face remote from the disc so as toregister with a'spigo't on to a corresponding face of the annular memberfor the adjacent disc.

'Go'nveniently the annular members for adjacent discs may be formed atthe radially outer ed ges'of their contiguous radial end faces in suchmanner as jointly to form a recess for receiving wld'meta'l rigidly toattach the rings one to the other.

practising the invention, the projection or projections on the discs maybe of any suitable form but it is'preferred to use a single continuousprojection of cylindrical shape. The radial positionof the projection orprojections will preferably be chosen so that during rotation at normalworking speed there will be little or no sheer stress at the radialplane between the projection or projections of a disc and the face of'thdisc F ggpgflflm I 'Wlth the projection or projections on a disc formedoylindrically and adapted to into annular space formed between aradially inner flange and a radially outer flange on the annular memberto which said projection or projections will be secured by pinning orriveting or bolting as aforesaid, the said annular member will beconstructed with said flanges spaced apart in the radial direction by adistance at least equal to the depth of the projection in the radialdirection together with an amount corresponding to the distances bywhich the radially outer face' of the inner flange and the radiallyinner face of the outer flange can be expected to move in the radialdirection whilst the welding operation is bein effected upon saidannular member; also, the depth in the axial direction of the annularspace formed between said radially inner and outer flanges will be suchthat, with the projection fitted properly in position between saidflanges for pinning or riveting or bolting thereto, the opposing radialsurfaces of the annular member and the projection within said space, areseparated by an amount at least equal to the distance in the axialdirection by which said radial surface of the annular member can beexpected to move during the welding operation.

In a preferred construction, the annular members are secured each to theappertaining disc by means of radial pins inserted at the radially innerend of a series of radial holes formed in the annular members and theprojection or projections of the disc, the contiguous annular membersbeing secured together by welding effected whilst the discs aretemporarily held tightly together and in coaxial relationship with eachother.

For some applications the discs may be formed without central bores, thetwo end discs in the assembly being attached, in similar manner to thatdescribed, to members forming stub shafts for the bearings. By theomission of central bores in the discs the overall length of the rotorto accommodate a given number of stages may be reduced since the dischubs will be more lightly stressed and may therefore be made narrowerthan is possible in the case where the discs are formed with centralbores.

To enable the invention to be fully understood reference is made to theaccompanying drawing, the sole figure of which is a half axial sectionalview of a portion of a turbine or compressor bladed rotor constructed inaccordance with the invention.

The rotor shown comprises a rigid assembly of discs I, 2, 3 which areformed separately and secured together in side-by-side and coaxialrelationship in a manner presently to be described. It will beappreciated that the discs will be shaped at the outer periphery asindicated for disc I at la so as to form a base for attachment theretoof one or more rows of blades (not shown).

For the attachment of the disc I to discs 2, 3, said disc I is formed onopposite end faces with integral cylindrical projections lb and larespectively; said projections are preferably located at such radialdistance from the axis of the disc that under the normal speed ofrotation about said axis there will be little or no sheer stress in theneighbourhood of the plane indicated at XX. Discs 2 and 3 are formedwith similar projections 20, 3b respectively facing, and at the sameradial distance from the axis as, the projections lb, lc for disc I.

.4 through the intermediary of two ring members 4 and 5 respectively.Rin 4 is formed with flanges 4a and 4b to provide a recess into whichthe disc projection lb fits with radial clearance 6. Likewise ring 5 isformed with flanges 5a and 5b providing a recess for receiving discprojection 2c also with radial clearance 6. After entry of the discprojection lb into position between ring flanges 4a, 4b, the ring isrigidly secured to the projection by headed pins 1 inserted incorresponding radial holes in the ring inner flange 4b and extendingthrough corresponding holes in the disc projection lb into holes in thering outer flange 4a. Similarly, ring 5 is rigidly secured to discprojection 20 by pins 8 passing through holes in the ring flanges 5a, 5band the disc projection 20.

With ring 4 secured as described to disc I, its radial end face remotefrom the disc registers with spigot on to the corresponding radial endface of ring 5 attached to disc 2. On their outer periphery the rings 4and 5 are shaped jointly to provide a circumferential recess for thereception of weld metal 9 for rigidly attaching together the rings 4 and5 and therewith the discs I and 2. It will be appreciated that theweldin operation will be effected while the discs I and 2 aretemporarily held tightly together and in coaxial relationship with eachother so that the rings 4 and 5 will be firmly held together with theirfacin radial end surfaces closely engaged.

In similar manner to that just described in respect of the attachment ofdiscs I and 2, the discs I and 3 are rigidly attached together by meansof rings l4 and I5 fitting over the disc projections 3b and [0respectively with radial clearance l6, which rings after being securedto said disc projections by pins l1 and I8 respectively are subsequentlywelded together at l 9.

With the construction shown and described and subject to the clearance6, l6 being suitably dimensioned, the discs I, 2 and 3 can be rigidlyconnected together without introduction of local stresses into the discsduring the welding operation.

In the construction specifically shown and described the discs I, 2 and3 are formed with a central bore l0 for assembly on a shaft. In analternative construction the discs may be formed without central boresand the outer faces of the two end discs of the rotor are formed eachwith a projection or projections to which a member may be secured in themanner described above, which members form stub shafts for the bearings.In this construction the disc hubs will be more lightly stressed and maytherefore be made narrower than is indicated in the drawing, thusenabling the overall length of the rotor to be reduced.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A rotor for a multi-stage turbine or compressor, comprising aplurality of discs having projections integral therewith and directedfrom the opposing sides of adjacent discs, annular members mounted onsaid projections, and a weld securing said members together, saidannular members being formed with two axially directed radially spacedannular flanges which receive the projections with clearance between theprojections and the radially inner flanges of the respective annularmembers, and fastening means extending radially through the flanges Theattachment f is I to dis 2 i ef e of the annular members and therespective projections and securing the annular members to therespective discs.

2. A rotor for a multi-stage turbine or compressor, comprising aplurality of discs having annular projections integral .with therespective discs and directed toward one another from the opposing sidefaces of adjacent discs, annular members mounted on the projections onthe respective discs, and a weld securing said members together, each ofsaid annular members being formed with two axiall directed radiallyspaced annular flanges which receive the annular projection on therespective disc with clearance between the projection and the radiallyinner flange of the respective annular member, and fastening meansextending radially through the flanges of each annular member and therespective projection and securing the annular members to the respectivediscs.

3. .A rotor for a multi-stage turbine or compressor, comprising aplurality of discs each having an annular projection on a side facethereof and integral therewith and directed axially toward the opposingside face of an adjacent disc, an annular member mounted on theprojection on one disc, an annular member mounted on the projection onan adjacent disc, and a weld securing the annular members together, eachof said annular -members bein formed with two axially directed annularflanges spaced radially to receive the axially directed annularprojection on the respective disc with clearance between the radiallyinner flange of the annular member and the respective projection, andthe annular members being formed on their meeting faces one with asurface and the other with a cooperating flange to locate said membersconcentrically with the discs for welding together.

4. A rotor for a multi-stage turbine or compressor, comprising at leasttwo coaxially arranged discs each having a plurality of projectionsintegral therewith and extending axially therefrom toward the adjacentdisc, an annular member secured on the projections on each disc andhaving two axially directed flanges forming a housing for the respectiveprojections with clearance between each projection and the radiallyinner of said two flanges of the respective annular member, said annularmembers bein formed on their meeting faces one with a surface and theother with a flange which cooperate to locate said members and the discssecured thereto concentrically for welding together.

5. A rotor for a multi-stage turbine or compressor, comprising at leasttwo coaxially arranged discs, each of the discs having on the surfacethereof which faces the other disc an annular axially directedprojection arranged concentrically with the rotor axis andintermediately between said axis and the periphery of the disc, anannular member mounted on each of said projections and having radiallyinner and radially outer axially projecting flanges forming a space forreceiving the respective projection with clearance between the radiallyinner flange and the projection, and fastening means extending radiallythrough said flanges of each annular member and the respectiveprojection, the meeting surfaces of the annular members of the two discsbeing provided with cooperating parts which locate said members and thediscs secured thereto concentrically with the axis of the rotor, and theradially outer edges of said members adjacent to their meeting surfacesbeing shaped to provide a recess for receiving weld metal.

KARL BAUMANN.

REFERENCES CITED The following references are of record in the flle ofthis patent:

UNITED STATES PATENTS Number Name Date 1,399,816 Spiers Dec. 13, 19212,369,051 Huber Feb. 6, 1945 FOREIGN PATENTS Number Country Date 341,892Germany Oct. 1921

